Magnetic coupler

Abstract

A magnetic coupler having higher response is provided. The magnetic coupler includes a thin film coil wound in a first layer; a first MR element being disposed in a second layer, and detecting an induced magnetic field generated by a signal current flowing through the thin film coil; and yokes being disposed close to the first MR element, and including a soft magnetic material. The first MR element is disposed in a position corresponding to a linear region of the thin film coil in a stacking direction. The yokes are disposed at both of an inner turn side and an outer turn side of the thin film coil in a manner of interposing the first MR element in the second layer. Thus, reduction in intensity of the induced magnetic field is suppressed, and intensity distribution of the induced magnetic field becomes flatter.

1. A magnetic coupler,
 comprising: 
 a thin film coil wound in a first layer, 
 a plurality of magnetoresistive elements located in a second layer different from the first layer to detect an induced magnetic field generated by a current flowing through the thin film coil, and 
 a plurality of yokes spaced apart from the plurality of magnetoresistive elements, located only in the second layer without overlapping one another, with a first yoke disposed to an inner turn side and a second yoke to an outer turn of the thin film coil, with a portion of the plurality of magnetoresistive elements in between, in a radial direction of the thin film coil. 
 
     
     
       2. The magnetic coupler according to  claim 1 :
 wherein 
 the thin film coil has a linear region including a plurality of linear patterns which linearly extends in a winding direction of the thin film coil, and 
 each of the plurality of magnetoresistive elements is provided in a position corresponding to the linear region. 
 
     
     
       3. The magnetic coupler according to  claim 1 :
 wherein 
 in the radial direction of the thin film coil, a distance from the first yoke at the inner turn side to a middle point is smaller than a distance from the second yoke at the outer turn side to the middle point, the middle point being defined as a median point between an innermost turn edge and an outermost turn edge of the thin film coil. 
 
     
     
       4. The magnetic coupler according to  claim 1 :
 wherein 
 in the radial direction of the thin film coil, the first yoke at the inner turn side is located at an outer turn side of the innermost turn edge of the thin film coil. 
 
     
     
       5. The magnetic coupler according to  claim 1 :
 wherein 
 in the radial direction of the thin film coil, an inner side edge of the second yoke at the outer turn side is located at an inner side of the outermost turn edge of the thin film coil. 
 
     
     
       6. The magnetic coupler according to  claim 1 :
 wherein 
 each yoke has a magnetization easy axis in a direction along a winding direction of the thin film coil. 
 
     
     
       7. The magnetic coupler according to  claim 6 :
 wherein 
 said each yoke extends such that a longitudinal direction of said each yoke corresponds to the winding direction of the thin film coil. 
 
     
     
       8. The magnetic coupler according to  claim 1 :
 wherein 
 each yoke includes a plurality of yoke patterns dividedly arranged to be adjacent to one another in the radial direction of the thin film coil, each of the yoke patterns extending along the winding direction of the thin film coil. 
 
     
     
       9. The magnetic coupler according to  claim 1 :
 wherein 
 each yoke has a stacked structure having soft magnetic layers and insulating layers alternately stacked in the stacking direction. 
 
     
     
       10. The magnetic coupler according to  claim 1 :
 wherein 
 the magnetic coupler further includes an antiferromagnetic layer having magnetic moment in a direction along a magnetization easy axis of the yoke. 
 
     
     
       11. The magnetic coupler according to  claim 1 :
 wherein 
 the magnetic coupler further includes ferromagnetic layers applying a bias magnetic field to the yoke in a direction along a magnetization easy axis of the yoke. 
 
     
     
       12. The magnetic coupler according to  claim 1 :
 wherein 
 each magnetoresistive element has a plurality of strip-shaped patterns extending along a winding direction or in the radial direction of the thin film coil, and 
 the plurality of strip-shaped patterns are connected in series to one another. 
 
     
     
       13. A magnetic coupler,
 comprising: 
 a thin film coil wound in a first layer, 
 first to fourth magnetoresistive elements located in a second layer different from the first layer, and having resistance values which are variable depending on an induced magnetic field generated by a current flowing through the thin film coil respectively, and 
 a plurality of yokes spaced apart from the first to fourth magnetoresistive elements, located only in the second layer without overlapping one another, a first and second yoke disposed to an inner turn side and third and fourth yoke an outer turn side of the thin film coil, with the first and second magnetoresistive elements in between the first and third yokes and the third and fourth magnetoresistive elements in between the second and fourth yokes, in a radial direction of the thin film coil; 
 wherein 
 a resistance value of each of the first and second magnetoresistive elements changes in a direction opposite to an up-down direction of a resistance value of the third and fourth magnetoresistive elements, respectively, in response to changes of the induced magnetic field.